Heat insulation material



Patented Sept. 17, 1940 UNITED STATES PATENT criss- HEAT INSULATION MATERIAL Albert 'S. Johnson, Oak Park, Ill.

No Drawing. Application March 21, 1938, Serial No. 197,220

1 Clain'i.v

My invention pertains to heat-insulating compounds or mixtures and it relates more particularly, but not exclusively, to insulating mix tures of a plastic character designed and adapted to be used in connection with boilers or the like to retain the heat therein, resulting in marked improvement in the economy of operation of the boilers or heaters with which it is used to cover the brick-work, concrete, or its equivalent externally.

The present preferred formula is substantially as follows by weight:

Per cent Gilsonite with a melting point of 270 to Parolite with a melting point of about 200 F 18.0 Flux asphalt (Saybolt Universal Visco. at

100 F., S. O. C.-1.00) 4.4 Kerosene 20. Asbestos fibre 22.9 Calcium carbonate 11.3 Diatomac'eous earth 12.6

Mineral spirits 4.6

The gilsonite which is a natural mined product and is one of the purest forms of asphalt with a melting point or from about 270 to 300 F. comprises an asphalt water-proofing binder which forms a part of the vehicle solids imparting hardness to the mass. Several other natural asphalts could be used either to replace or with the gilsonite, such as grahamite, wurtzilite, uintaite, elaterite, these latter'having higher melting points and lower penetration than gilsonite and they are also higher in cost and are not as readily obtainable. The parolite is a blown asphalt water-proofing binder which forms a part of the vehicle solids and imparts elasticity to the mass. The term blown asphalt applies especially to residual asphalts, starting with a melting point of 85 to 125 F., and that is to be considered as quite generic, heating the asphalt to well above its melting point, and blowing with air. The characteristics of the asphalt are changed in that the meltused to blend the gilsonite and Parolite together in a homogeneous state, these fluxing asphalts being residual asphalts, having no further treatment to change their chemical or physical properties. They remain at a very low melting point and have very high penetrations, but they blend asphalts, and the high belting point natural asphalts, under heat to give compatible black varnishes.

The kerosene employed is a reducing agent, that is to say, a thinner. It is added to the plastic because of its slow evaporation rate, allowing the plastic to settle to the brickwork and to form an integral bond.

The asbestos-fiber constitutes a combined filler and binder, and is preferably, but not necessarily, a Canadian-mined asbestos having extremely long, tough fibre giving strength and heat insulation.

The calcium-carbonate constitutes a filler imparting density, and a preferred material, known as Surfex, is used which is a form of calciumcarbonate and this can be employed either with, or replacing ordinary calcium-carbonate.

The diatomaceous earth comprises a filler and. it. gives the mixturedensity and insulating properties clue to the fact that the structure of diatomaceous earth is very high in voids or multiple air-cells, which is quite necessary in a material of this kind.

The mineral spirits represent a reducing or thinning agent and they may be in the form of Oleum or Napoleurn having a distillation range of from 300 to 400 with a relatively rapid evaporation rate. Oleum imparts the working property to a plastic composition.

The gilsonite, Parolite and flux asphalt are melted together and then reduced with the kerosene and mineral spirits, the resulting liquid being allowed to cool, and then the asbestosfibre, calcium-carbonate and diatomaceous earth are placed in the liquid in the order named and thoroughly mixed to form a uniform product.

Such product is in paste condition and it is applied to the brick-work around and over the boiler by a trowel or otherwise to a suitable thickness, say, for example, three-eighths of an inch. This coating is slow-hardening and gradually solidifies, such hardening at leastin some instances being confined to the surface.

It is a common erroneous belief among brickset boiler owners that bricks act as an insulating agent enabling the boiler to retain its maximum heating efiiciency, whereas the truth of the matter is that bricks are porous and actually breatheallowing the heat to escape and foreign drafts and moisture to enter.

The new plastic insulation referred to above, unlike other products on the market, affords complete insulation for brick-set boilers and it covers the entire brickwork of the boiler, completely blanketing all joints and cracks and in this way preventing also corrosion of boiler-plate by excluding moist air and Water.

The novel plastic insulation detailed above does not crack, chip, or peel, thereby allowing more frequent washing down of the boiler,

this being largely due to the proper preparationbefore application of the plastic material.

The use of the new and improved plastic insu-.

brick-work, especially at the front of the boiler around the boiler-plate, cleanout doors, and on the arch where the drafts are strongest, impairing the efficiency of the boiler, but the use of the new plastic insulation covers all brick-work like a glove, fills all cracks, and permits all drafts through the fire-box which allows the boiler to give maximum heating economy.

Those acquainted with this art will readily understand that the invention is not necessarily limited to the precise and exact details specified above and that various changes and-modifications may be resorted to without departure from the heart and essence of the invention, as defined 12.6% diatomaceous-earth,4.6% mineral-spirits.

ALBERT S. JOHNSON, 

